Propeller assembly

ABSTRACT

A propeller assembly comprises a plurality of hubs mounted for rotation on an axis which is transverse to the direction of movement of the boat, each hub haVing a plurality of radially extending blades which are curved and present crowned, convex surfaces to the water. The assembly is disposed, either within the boat or attached to the rear transom, so that when the boat is in motion the hubs are tangent to the surface of the water and press down on the surface of the water, and the blades slide into, and out of, the water endwise. The blades on the hubs of a paIr of hubs are opposed and angularly related one to the other so that they impel water inwardly toward one another and back, or outwardly away from one another and back, but not upwardly.

United States Patent Dunham [15] 3,682,128 1451 Aug. 8, 1972 [54]PROPELLER ASSEMBLY [72] Inventor: Wayne Dunham, PO. Box 22719,

Fort Lauderdale, Fla. 33315 [22] Filed: Sept. 10, 1970 [21] Appl. No.:71,049

[52] US. Cl. ..l15/34 R [51] Int. Cl. .3631! 5/08 [58] Field of Search..1 15/34, 35, 37, 49, 50

[56] References Cited UNITED STATES PATENTS 685,591 10/1901 Femez et al...1 15/17 2,357,084 8/1944 Cleofen 1 15 I9 3 2,391,109 12/ 1945 Patten.-.1 15/49 3,327,674 6/ 1967 Schwarzer ..1 15/49 X PrimaryExaminer-Milton Buchler Assistant Examiner-Carl A. Rutledge Attomey-JohnW. Hoag ABSTRACT A propeller assembly comprises a plurality of hubsmounted for rotation on an axis which is transverse to the direction ofmovement of the boat, each hub haV- ing a plurality of radiallyextending blades which are curved and present crowned, convex surfacesto the water. The assembly is disposed, either within the boat orattached to the rear transom, so that when the boat is in motion thehubs are tangent to the surface of the water and press down on thesurface of the water, and the blades slide into, and out of, the waterendwise.

The blades on the hubs of a pair of hubs are opposed and angularlyrelated one to the other so that they impel water inwardly toward oneanother and back, or outwardly away from one another and back, but notupwardly.

W/YTER LINE PATENTEBAuB 8:912 3,682,128

snmzufz INVENTOR. Wayne film/lam PROPELLER ASSEMBLY FIELDOF THEINVENTION This invention relates to a propeller assembly for drivingboats, and particularly racing boats known as three point hydros. Thepropeller means can be adapted to inboard and outboard andinboard-outboard power plants.

At the present time the worlds fastest propeller.

driven boats when under way, ride on their sponsons and one-half oftheir surfacing propellers. The propellers are of conventional form' androtate around an axis parallel to the direction of travel of the boat.This arrangement is unsatisfactory and inefficient because thedisposition of the propeller blades produces only a limited forwardthrust. The propeller means of earlier boat power plants was even moreunsatisfactory because the propeller shaft, bearings and supportingstruts, extend into the water and are a drag on the boat and the forwardthrust of the blades is opposed by the thrust of the blades as theyenter and leave the water.

An object-of the invention is to provide propeller means for boats whichwill reduce the wetted surface and parasitic drag and thereby makepossible increased speed power output.

Another object of the invention is to lessen friction, heat and powerloss by providing propeller means without underwater shafts, bearing andstruts and all underwater non-working machinery.

Another object of the invention is to provide propeller means such thata hub and blades assembly may be readily removed from its mounting shaftand replaced by another such assembly.

SUMMARY OF THE DESCRIPTION The propeller means comprising a propellerassembly resemble the rear wheels of an automobile in that they aredriven in coordinated pairs from differential type gearing and rotatelongitudinally rather than laterally of the vehicle. Each prop'ellermeans comprises a hub mounted for rotation on a driven shaft and havinga plurality of radially projecting blades which are each curved andpositioned so that the crowned convex surfaces of the blades contact thewater, the blades entering and leaving the water at an angle to reduceto a minimum any thrust counter to their forward thrust delivered whileimmersed in the water.

Boats of the kind for which the disclosed propeller is intended havevery little draft and when moving tend to ride up so that the boatplanes over the water. The propeller assembly disclosed herein issupported, with the propeller means either disposed within one or morewells within the boat, or attached to the outside of the boat transom,or supported at the lower end of an outboard motor attached to thetransom, in such a way that when the boat planes over the water the hubsof the propeller members will be substantially tangent to, and ridingon, and pressing down on, the surface of the water.

Preferably the propeller members are mounted so that their opposedblades will be angularly related and will impel water inwardly towardone another and back, or outwardly away from one another and back, butnot up upwardly.

DESCRIPTION The propeller means which is the subject of this inventionmay be used with, and form part of, inboard, outboard andinboard-outboard power plants. Since this invention relates only to thepropeller means and not to the structure of the boat or motor with whichit is employed the latter are not described in detail.

However, the invention will best be understood by reading the followingdescription in connection with the drawings, which illustrate thepropeller means in association with inboard, outboard, andinboard-outboard power plants, and in which;

FIG. 1 is a rear end elevation of a propeller assembly embodying theinvention, looking at the stern transom of a boat employing theassembly,

FIG. 2 is a view taken on the lines 2-2 of FIG. 1,

FIG. 3 is similar to FIG. 2 but is a perspective view looking at one ofthe propeller members from a 30 angle,

FIG. 4 is a perspective view showing the propeller assembly employed aspart of an inboard-outboard'installation,

FIG. 5 is a side elevation of the embodiment shown in FIG. 4,

FIG. 6 is a side elevation of the assembly employed as part of anoutboard motor, and

FIG. 7 is a perspective view showing the rear end of a boat providedwith downwardly opening wells in which the pair of hub and blade memberscomprising the assembly are respectively mounted.

In the embodiment of the invention illustrated in FIG. 1 a pair of hubs10,, and 10, are shown mounted adjacent the outer ends of shafts 12,,and 12,, held in place by the quick release nuts 14. Shafts 12,, and12,, extend through, and are mounted by, the angularly related,downwardly and inwardly inclined walls 16,, and 16,, of a housing 18. Atthe inner ends of shafts 12,, and 12,, respectively are the bevel gears20,, and 20,, which mesh with the ring gear 22 carried by a drive shaft24, which may comprise part of a known power plant suitable for theboat-in connection with which the propeller means is employed.

Projecting radially from hubs 10,, and 10 respectively are the blades26,, and 26,, which, as will be seen by reference to FIGS. 2 and 3, areeach curved longitudinally and laterally and the crowned convex surface28 of each blade is its leading surface. Two or more blades are carriedby each hub and the inner ends of the blades are angularly related tothe periphery of the hub somewhat like successive turns of a spiralthread.

The blades on one hub are disposed in opposed relation to the blades onthe other hub and the blades of opposed pairs of blades are oppositelyinclined so that the forward thrust of the blades in the water displaceswater rearwardly and laterally toward one another. The curvature of theblades, best seen in FIG. 3, is such that the leading edge 30 of eachblade projecting radially from it will enter and exit from the watersubstantially parallel with the direction of movement of boat beingdriven by its propeller, much in the way a skilled canoeist willfeather" his paddle to make it enter and leave the waterwithoutsplashing and to prevent the smoothness and power of the forward thrustof the paddle being lessened and impaired as would be the case ifentrance into, and exit from,the the water. The result of this bladestructure substantially prevents the blades from displacing waterdownwardly as they enter the water, and from lifting water as they leavethe water,

1 without impairing the thrust of the blades on the water as they aremoving substantially parallel with the surface of the water. This resultpromotes efficiency and increases the speed potential of the boat bothbecause the forward thrust of the blades is not lessened by an upwardthrust having opposing force components, and by maintaining the smootheven riding of the boat which would be impaired by the turbulence androcking motion occasioned by a blade striking the water broadside as itenters the water and lifting water as it exits from the water.

As is illustrated in FIGS. 4-7 as well as in FIG. 1 propeller assemblyis mounted inside or outside a boat at a level such that when the boatplanes over the water the peripheries of the hubs will be substantiallytangent to the surface of the water and the blades will each movesuccessively through air and water during each rotation of the hub. Theperiphery of the hubs may be inclined outwardly and toward their axes,as indicated by numeral 32 in FIGS. 1 and 4, to compensate for theinclination of shafts 12, and 12 and present a surface which will beflat and parallel with the surface of the water, and will tend to rideon the surface of the water while rotating with said shafts, and pressdown on the surface of the water.

In the embodiment of the invention illustrated in FIG. 4 the triangularshaped housing 18 is extended rearwardly and downwardly below thepropeller assembly, the extension 32 serving both to protect thepropeller assembly in shallow water and to serve as a rudder. As shownin FIG. the housing 18 is hinged as indicated at 34, to means 36projecting rearwardly from the rear transom 38 of a boat 40 within whichis an engine 42 of known kind.

In FIG. 6 a propeller assembly embodying the invention is shownincorporated in an outboard motor 44 of known kind which is attached tothe rear transom by conventional clamp means 46 pivotally connected tothe outboard motor by pivot 48 so that the motor assembly including thepropeller means may be pivoted to lift-the propeller means inconventional manner, as when in shallow water.

FIG. 7 illustrates an inboard installation in a boat having two upwardlyopening walls 50 and 50,. It will be understood that a propeller numbercomprising a hub and radially projecting blades will be mounted in eachwell on opposite sides of a rudder 52 with the periphery of the hubsdisposed at the level of the water.

Because the hubs 10,, and 10,, are mounted outside the housing 18 theyare readily available and an injured hub and blades member may bequickly replaced with a similar uninjured member, this action beingfacilitated by the use of the quick release nuts 14.

There has thus been provided a propeller assembly for boats in which theabove mentioned objects are attained in a simple and practical way.

What I claim is: t

l. A propeller assembly for a boat having a longitudinally extendingdrive shaft with a ring gear thereon, reactants-tea 'vttes gz'a wttt ssmthe ring gear, said shafts being inclined downwardly and outwardly fromthe center of the ring gear, a pair of hubs mounted on said shaftsrespectively, the said shafts being disposed so that the hubs extendsubstantially to the water line, each hub having a plurality of radiallyprojecting blades which are curved longitudinally and laterally anddefine a transversely extending crowned convex surface between leadingand trailing edges which are substantially parallel with the boat sothat each blade enters and exits from the water substantially parallelwith the movement of the boat being driven by the propeller and so thatduring each rotation of a blade its crowned convex surface becomes itsleading surface and acts to push water downwardly and inwardly towardthe opposed blade supported on the other hub, the hubs being disposed sothat when the boat planes over the water the peripheries of the hubs aresubstantially tangent to the surface of the water and the blade means onthe hubs converge downwardly toward one another.

2. The structure claimed in claim 1, in which the ring gear of the driveshaft is disposed within a housing having downwardly and inwardlyinclined walls, the hubs are disposed substantially parallel with thedownwardly and inwardly inclined walls of the housing, and the bladeswhich project from one hub act during each rotation to push waterlaterally toward and under the other hub and against the blade meansprojecting from the other hub.

1. A propeller assembly for a boat having a longitudinally extendingdrive shaft with a ring gear thereon, which comprises, a plurality ofshafts having at their inner ends respectively beveled gears which meshwith the ring gear, said shafts being inclined downwardly and outwardlyfrom the center of the ring gear, a pair of hubs mounted on said shaftsrespectively, the said shafts being disposed so that the hubs extendsubstantially to the water line, each hub having a plurality of radiallyprojecting blades which are curved longitudinally and laterally anddefine a transversely extending crowned convex surface between leadingand trailing edges which are substantially parallel with the boat sothat each blade enters and exits from the water substantially parallelwith the movement of the boat being driven by the propeller and so thatduring each rotation of a blade its crowned convex surface becomes itsleading surface and acts to push water downwardly and inwardly towardthe opposed blade supported on the other hub, the hubs being disposed sothat when the boat planes over the water the peripheries of the hubs aresubstantially tangent to the surface of the water and the blade means onthe hubs converge downwaRdly toward one another.
 2. The structureclaimed in claim 1, in which the ring gear of the drive shaft isdisposed within a housing having downwardly and inwardly inclined walls,the hubs are disposed substantially parallel with the downwardly andinwardly inclined walls of the housing, and the blades which projectfrom one hub act during each rotation to push water laterally toward andunder the other hub and against the blade means projecting from theother hub.